Clipping settings on Mirror Modifier
When you mirror an object with a mirror modifier, it is not necessary to always put the last vertices on the mirroring axis. What to do if you don't want to line the last vertices one by one to save time?
- Turn the clipping on, on the modifier settings.
This way you can just pass the vertices further the axis and it should mirror just fine. As mentioned above, can be useful to save some time.